Adaptive backrest assembly and seat

Abstract

The utility model discloses a kind of self-adapting backrest components and seat, self-adapting backrest component includes backrest support, backrest frame, connecting seat;Connecting seat is movably installed on backrest support, recess is provided on backrest support, stop block is provided on connecting seat, spring is provided in recess, the upper end portion of spring is abutted on stop block, lower end portion is abutted in the lower end surface of recess;Backrest frame is installed in connecting seat, lock block is provided on connecting seat, lock block can move between the first position of one and the second position of rear storage in connecting seat, protrude in connecting seat, a plurality of clamping position slots arranged along up-down direction are provided on backrest frame, when lock block is in first position, it can be clamped into one of clamping position slots to limit the freedom of backrest frame downward movement relative to connecting seat, when lock block is in second position, it is separated from clamping position slot. The utility model improves the comfort of seat, and increase the application range of seat backrest.

Description

Technical Field

[0001] This utility model relates to the field of seating technology, specifically to an adaptive backrest assembly and a seat. Background Technology

[0002] Traditional chairs have a fixed backrest and seat cushion, and the distance between the backrest support and the seat cushion is fixed, making it unsuitable for different sitting postures and body shapes. Some existing office and study chairs, in an effort to improve comfort and allow the backrest support to adapt to different postures and body shapes, have incorporated two relatively movable parts into the backrest. This involves a vertically movable frame installed at the front of the backrest assembly's support bracket, with the backrest support positioned on this frame. An elastic buffer mechanism is placed between the frame and the support bracket. While this backrest assembly can adapt to the user's back height, the frame's vertical movement is relatively limited, making it difficult to adapt to a wide range of back positions and thus limiting its applicability. Utility Model Content

[0003] The purpose of this invention is to provide an adaptive backrest assembly and seat that can adapt to the user's back height position within a wide range, thereby increasing the seat's applicability.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] An adaptive backrest assembly, including a backrest bracket, a backrest frame, and a connector;

[0006] The connecting seat is movably mounted on the backrest bracket so that the connecting seat can move relative to the backrest bracket in the vertical direction. The backrest bracket is provided with a groove that is recessed from its front side and extends in the vertical direction. The connecting seat is provided with a stop block that extends into the groove. A spring is provided in the groove, with the upper end of the spring abutting against the stop block and the lower end abutting against the lower end face of the groove.

[0007] The backrest frame is mounted on the connecting seat and configured to move relative to the connecting seat in the vertical direction. The connecting seat is provided with a locking block that can move between a first position protruding forward from the connecting seat and a second position retracting into the connecting seat. The backrest frame is provided with multiple locking slots arranged in the vertical direction. When the locking block is in the first position, it can be engaged in one of the locking slots to limit the degree of freedom of the backrest frame to move downward relative to the connecting seat. When the locking block is in the second position, it disengages from the locking slot.

[0008] Preferably, the connecting seat includes a front wall and two side walls extending rearward from both sides of the front wall. The two side walls are respectively placed on both sides of the backrest bracket. Each side wall is provided with two limiting grooves extending in the vertical direction. A guide post that slides through the limiting groove is fixedly connected to the side of the backrest bracket.

[0009] Preferably, the guide post is detachably fixed to the side of the backrest bracket, and the guide post is provided with a limiting rib protruding outward from its periphery, the limiting rib being located on the outer side of the side wall of the connecting seat.

[0010] Preferably, the connecting seat is provided with a guide groove, which includes a first section extending vertically and a second section extending from the bottom of the first section toward the backrest frame. A guide post is provided on the locking block, and the guide post is slidably embedded in the guide groove. The guide post slides within the second section of the guide groove to move the locking block between a first position and a second position. The backrest frame is provided with a first pushing part located above multiple locking slots and a second pushing part located below multiple locking slots. A third pushing part is provided between the lowest locking slot and the second pushing part on the backrest frame. The third pushing part is used to... When the frame slides downwards and the third pushing part contacts the locking block, it pushes the locking block from the first position to the second position, so that the guide post slides to the position where the first and second sections of the guide groove meet. The second pushing part is used to push the locking block upwards when the backrest frame slides upwards and the second pushing part contacts the locking block. The first pushing part is used to push the locking block downwards when the backrest frame slides downwards and the first pushing part contacts the locking block. An elastic element is provided between the connecting seat and the locking block. This elastic element is used to apply elastic stress to the locking block so that the locking block always maintains the tendency to move towards the first position.

[0011] Preferably, a lock box located above the stop block is detachably fixed on the connecting seat. The lock box is provided with a mounting groove with an opening facing the backrest frame. A guide groove is provided on each side of the mounting groove. The lock block is embedded in the mounting groove. The two ends of the guide post protrude from the two sides of the lock block and are respectively embedded in the two guide grooves. The elastic element is a spring, and the two ends of the spring abut against the bottom wall of the mounting groove and the lock block respectively.

[0012] Preferably, a sliding groove is provided on each side of the mounting groove. The sliding groove is located below the guide groove and extends in the vertical direction. A sliding post is provided on the locking block. The two ends of the sliding post protrude from the two sides of the locking block and pass through the two sliding grooves. The sliding post is configured to slide along the extension direction of the sliding groove and rotate within the sliding groove.

[0013] Preferably, the locking block is provided with a locking protrusion that matches the shape of the locking groove; the locking groove includes a baffle wall and an inclined guide wall, the inclined guide wall gradually slopes away from the connecting seat from bottom to top, the baffle wall extends from the top of the inclined guide wall towards the connecting seat, the baffle wall is parallel to the front-back direction or gradually slopes downward from front to back; when the locking protrusion is placed in the locking groove, the baffle wall abuts against the locking protrusion to limit the degree of freedom of the baffle wall to move downward relative to the locking protrusion, and the inclined guide wall is used to push the locking protrusion toward the connecting seat when the backrest frame moves upward relative to the locking block so that the locking block disengages from the locking groove.

[0014] Preferably, the backrest frame is provided with a clearance groove that extends vertically to accommodate the lock block. A first pushing part is provided at the top of the clearance groove, a second pushing part is formed at the bottom of the clearance groove, and a third pushing part is a pushing slope provided in the clearance groove. The pushing slope gradually slopes from top to bottom toward the direction of the connecting seat.

[0015] Preferably, the backrest frame is provided with vertically extending guide grooves, and the connecting seat is provided with vertically extending guide rails, which are slidably embedded in the guide grooves.

[0016] Seats, including the aforementioned adaptive backrest assembly.

[0017] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0018] In this invention, the backrest assembly can adapt to the height position of the user's back. When using the chair, the backrest frame can always provide the best support for the user's back, improving the comfort of the chair. In addition, the user can adjust the height position of the backrest frame relative to the connecting seat by using the locking block according to their own sitting posture and body shape. When the adaptive movement of the backrest frame cannot obtain a good support effect, the user can adjust the height position of the backrest frame relative to the connecting seat, thereby increasing the applicability of the chair backrest. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of this utility model;

[0020] Figure 2 This is a cross-sectional view of the present invention;

[0021] Figure 3 for Figure 1 Assembly diagram of the central locking block and the lock box;

[0022] Figure 4 for Figure 1 A schematic diagram of the backrest frame;

[0023] Figure 5-8 This is a schematic diagram of the adjustment process of this utility model.

[0024] The components are as follows: 10. Backrest bracket; 11. Guide post; 12. Groove; 20. Connecting seat; 21. Front wall; 22. Side wall; 23. Limiting groove; 24. Guide rail; 25. Stop block; 30. Backrest frame; 31. Locking groove; 311. Stop wall; 312. Slanted guide wall; 32. Clearance groove; 321. First pushing part; 322. Second pushing part; 323. Third pushing part; 33. Guide groove; 40. Spring; 50. Locking block; 51. Snap-fit ​​protrusion; 52. Guide post; 53. Sliding post; 60. Lock box; 61. Mounting groove; 62. Guide groove; 621. Second section; 622. First section; 63. Sliding groove; 70. Spring. Detailed Implementation

[0025] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments. Unless otherwise specified, the materials and equipment used in this embodiment are all commercially available. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0026] In the description of this application, it should be understood that the terms "upper," "lower," "front," "rear," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. In the description of this application, "a plurality of" means two or more, unless otherwise precisely specified.

[0027] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "connected," "linked," and "connected" should be interpreted broadly. For example, they can refer to a fixed connection, a connection through an intermediary, or a connection within two elements or an interaction between two elements. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0028] like Figure 1 , 2As shown in Figures 3 and 4, this utility model provides an adaptive backrest assembly, which includes a backrest support 10, a backrest frame 30, and a connecting seat 20. The connecting seat 20 is movably mounted on the backrest support 10, allowing it to move relative to the backrest support 10 in the vertical direction. A groove 12 extending vertically is provided on the backrest support 10, formed by a recess from the front side of the backrest support 10 towards the rear. The opening of the groove 12 faces the connecting seat 20, which is located on the front side of the backrest support 10. A stop 25 extending into the groove 12 is provided on the connecting seat 20. A spring 40 is provided inside the groove 12, with its upper end abutting against the stop 25 and its lower end abutting against the lower end surface of the groove 12. The backrest frame 30 is mounted on the connecting seat 20, and the backrest frame 30 and the connecting seat 20 are slidably engaged. This allows the backrest frame 30 to have the freedom to move in the vertical direction relative to the connecting seat 20. A locking block 50 is provided on the connecting seat 20. The locking block 50 can move between a first position that protrudes forward from the connecting seat 20 and a second position that is received rearward inside the connecting seat 20. The backrest frame 30 is provided with a plurality of locking slots 31 arranged in the vertical direction. When the locking block 50 is in the first position, the locking block 50 can be locked into one of the locking slots 31. The locking block 50 limits the degree of freedom of the backrest frame 30 to move downward relative to the connecting seat 20. In this way, the position of the backrest frame 30 and the connecting seat 20 is locked. When the locking block 50 is in the second position, it disengages from the locking slot 31. At this time, the locking block 50 no longer limits the degree of freedom of the backrest frame 30 to move downward, and the backrest frame 30 can be moved downward relative to the connecting seat 20.

[0029] In use, the user's back applies downward pressure to the backrest frame 30, causing the backrest frame 30 and connecting seat 20 to move downwards. The connecting seat 20 then pushes the spring 40 downwards. As the spring 40 deforms, its upward elastic stress on the connecting seat 20 gradually increases. When the elastic stress of the spring 40 balances the downward pressure from the user's back, the downward position of the backrest frame 30 precisely adapts to the height of the user's back. This allows the backrest assembly to adapt to the height of the user's back, ensuring optimal support for the user's back during use and enhancing seat comfort. Furthermore, the user can adjust the height of the backrest frame 30 relative to the connecting seat 20 using the locking block 50 according to their posture and body shape. When the adaptive movement of the backrest frame 30 fails to provide optimal support, adjusting the height of the backrest frame 30 relative to the connecting seat 20 expands the applicability of the seat back.

[0030] In a preferred embodiment, the connecting seat 20 includes a front wall 21 and two side walls 22. The two side walls 22 extend rearward from both sides of the front wall 21 and are respectively placed on both sides of the backrest bracket 10. The front wall 21 and the two side walls 22 form a groove, so that the backrest bracket 10 is embedded in the groove, reducing the front-rear dimension of the backrest assembly. Each side wall 22 is provided with two limiting grooves 23 extending in the vertical direction. Two guide posts 11 are fixedly connected to the side of the backrest bracket 10. The two guide posts 11 slide through the two limiting grooves 23 on the side wall 22, thereby slidably mounting the connecting seat 20 on the backrest bracket 10. The guide post 11 is detachably fixed to the side of the backrest bracket 10. Specifically, the guide post 11 can be fixed to the side of the backrest bracket 10 with bolts. The guide post 11 is provided with a limiting rib protruding outward from its periphery. The limiting rib is located on the outside of the side wall 22 of the connecting seat 20. During assembly, the side wall 22 of the connecting seat 20 is placed outside the side of the backrest bracket 10. The guide post 11 is inserted into the limiting groove 23 from the outside of the side wall 22. The guide post 11 is then fixed to the backrest bracket 10 with bolts.

[0031] The connecting seat 20 is provided with a guide groove 62, which includes a first section 622 extending vertically and a second section 621 extending from the bottom of the first section 622 toward the backrest frame 30. The locking block 50 is provided with a guide post 52, which is slidably embedded in the guide groove 62. The guide post 52 can slide along the guide groove 62, thereby enabling the locking block 50 to move relative to the connecting seat 20 along the extension trajectory of the guide groove 62. When the guide post 52 slides inside the second section 621 of the guide groove 62, the locking block 50 can move between a forward first position and a rearward second position. When the guide post 52 slides inside the first section 622 of the guide groove 62, the locking block 50 can move relative to the connecting seat 20 in the vertical direction. The backrest frame 30 is provided with a first pushing part 321 located above multiple locking slots 31 and a second pushing part 322 located below multiple locking slots 31. A third pushing part 323 is provided between the lowest locking slot 31 and the second pushing part 322 on the backrest frame 30. The third pushing part 323 is used to push the locking block 50 from the first position to the second position when the backrest frame 30 slides downward and the third pushing part 323 contacts the locking block 50, that is, to push the locking block 50 backward so that the locking block 50 is away from the backrest frame 30. The second pushing part 322 is used to push the locking block 50 away when the backrest frame 30 slides upward and the second pushing part 322 contacts the locking block 50. The first pushing part 321 is used to push the locking block 50 downward when the backrest frame 30 slides downward and the first pushing part 321 contacts the locking block 50. A spring 70 is provided between the connecting seat 20 and the locking block 50. The spring 70 applies an elastic stress to the locking block 50, so that the locking block 50 always maintains the tendency to move towards the first position. That is to say, when the locking block 50 is not restricted by other parts, under the action of the elastic stress of the spring 70, the locking block 50 will always remain in the first position, so that the locking block 50 is locked into one of the locking slots 31, limiting the degree of freedom of the backrest frame 30 to move downward relative to the connecting seat 20, so that the backrest frame 30 is stably supported by the locking block 50.

[0032] To facilitate the installation of the locking block 50 and spring 70 onto the connecting seat 20, a lock box 60 located above the stop block 25 is detachably fixed to the connecting seat 20. The top of the lock box 60 can be hung on the connecting seat 20, and the bottom can be fixed to the connecting seat 20 with screws. The lock box 60 has a mounting groove 61 with an opening facing the backrest frame 30. A guide groove 62 is provided on each side of the mounting groove 61. The locking block 50 is embedded inside the mounting groove 61. The two ends of the guide post 52 protrude from the two sides of the locking block 50 and are respectively embedded in the two guide grooves 62. The two ends of the spring 70 abut against the bottom wall of the mounting groove 61 and the locking block 50, respectively. During assembly, the spring 70, locking block 50, and lock box 60 can be assembled into a single component, which is then installed onto the connecting seat 20. It should be noted that the spring 70 can be other elastic elements, such as a spring sheet or an elastic rubber block. A sliding groove 63 is provided on each side of the mounting groove 61. The two sliding grooves 63 are located below the two guide grooves 62 and extend in the vertical direction. A sliding post 53 is provided on the locking block 50. The two ends of the sliding post 53 protrude from the two sides of the locking block 50 and pass through the two sliding grooves 63. The sliding post 53 is configured to slide along the extension direction of the sliding groove 63 and rotate within the sliding groove 63. For example, the cross-section of the sliding post 53 can be set to a circle so that it can slide up and down along the sliding groove 63 and rotate relative to the lock box 60 within the sliding groove 63. When the sliding post 53 rotates relative to the lock box 60, the locking block 50 can swing relative to the connecting seat 20 in the front-back direction, thereby causing the locking block 50 to swing forward to a first position protruding from the front side of the connecting seat 20 and swing backward to a second position completely contained inside the connecting seat 20.

[0033] In the above structure, the sliding post 53 is used to set the locking block 50 to be able to swing between the first position and the second position, so as to avoid the locking block 50 from getting stuck. It should be noted that in other embodiments, the locking block 50 is not necessarily set to be swingable to realize its movement between the first position and the second position. For example, it is not necessary to set the sliding post 53 and the slide groove 63, so that the locking block 50 can move back and forth along the first section 622 of the guide groove 62 to realize the movement of the locking block 50 between the first position and the second position.

[0034] A locking protrusion 51 matching the shape of the locking groove 31 is provided on the locking block 50. When the locking block 50 is in the first position, the locking protrusion 51 protrudes from the front side of the connecting seat 20, thereby allowing the locking protrusion 51 to be embedded in the locking groove 31. The locking groove 31 includes a baffle wall 311 and an inclined guide wall 312, wherein the inclined guide wall 312 gradually slopes from bottom to top away from the connecting seat 20, that is, the inclined guide wall 312 gradually slopes forward from bottom to top, and the baffle wall 311 extends from the top of the inclined guide wall 312. Extending towards the connecting seat 20, that is, the baffle 311 extends from front to back, and the extension direction of the baffle 311 is parallel to the front-back direction, or the baffle 311 gradually slopes downward from front to back; when the locking protrusion 51 is placed in the locking groove 31, the baffle 311 abuts against the locking protrusion 51, and the baffle 311 and the locking protrusion 51 cooperate to limit the degree of freedom of the baffle 311 to move downward relative to the locking protrusion 51, thereby limiting the degree of freedom of the backrest frame 30 to move downward relative to the connecting seat 20. The inclined guide wall 312 is used to push the locking protrusion 51 toward the connecting seat 20 when the backrest frame 30 moves upward relative to the locking block 50. That is, by using the inclined structure of the inclined guide wall 312, the upward movement of the backrest frame 30 is transformed into the backward movement of the locking protrusion 51, so that the locking protrusion 51 disengages from the locking groove 31. That is, the locking block 50 disengages from the locking groove 31. After disengagement, the locking protrusion 51 can be locked into other locking grooves 31. In this way, the unidirectional movement of the backrest frame 30 relative to the connecting seat 20 is realized. That is, when the locking protrusion 51 is embedded in the locking groove 31, the backrest frame 30 can only be lifted upward. When the backrest frame 30 is pressed down, the locking block 50 can provide stable support for the backrest frame 30.

[0035] The backrest frame 30 is provided with an upward and downward extending clearance groove 32. The clearance groove 32 is used to accommodate the portion of the locking block 50 protruding from the front side of the connecting seat 20 to avoid the locking block 50. The first pushing part 321 is located at the top of the clearance groove 32, the bottom of the clearance groove 32 forms the second pushing part 322, and the third pushing part 323 is a pushing slope provided in the clearance groove 32. The pushing slope gradually slopes from top to bottom towards the connecting seat 20.

[0036] exist Figure 2 In the indicated state, if the backrest frame 30 is too low and needs to be adjusted upwards, the backrest frame 30 can be pulled upwards directly, causing the locking block 50 to engage with the lower-positioned locking slot 31, thus completing the upward adjustment of the backrest frame 30; Figure 2 In the indicated state, if the backrest frame at position 30 is too high, then... Figure 5As shown, pull the backrest frame 30 upwards so that the locking protrusion 51 on the locking block 50 contacts the third pushing part 323. Continue pulling the backrest frame 30 upwards, and the third pushing part 323 gradually pushes the locking block 50 backwards, causing the guide post 52 on the locking block 50 to slide along the first section 622 of the guide groove 62 to the position where the first section 622 connects with the second section 621. Continue pulling the backrest frame 30 upwards, and the locking block 50 is pushed upwards by the second pushing part 322, causing the guide post 52 to slide along the second section 621 of the guide groove 62 to the top of the second section 621. At this time, the locking block 50 is fixed in the second position and will not contact any of the locking slots 31; then as... Figure 6 As shown, when the backrest frame 30 is pressed down, since the locking block 50 is limited to the second position, it will not swing towards the backrest frame 30 under the action of the spring 70. At this time, the backrest frame 30 can move freely downward relative to the connecting seat 20 until the first pushing part 321 contacts the locking block 50; Figure 7 As shown, continue pressing the backrest frame 30 downwards. The first pushing part 321 pushes the locking block 50 downwards, causing the guide post 52 of the locking block 50 to slide downwards along the second section 621 of the guide groove 62 to the junction of the first section 622 and the second section 621. At this time, as shown... Figure 8 As shown, the locking block 50 is no longer limited by the second section 621 of the guide groove 62. Under the elastic stress of the spring 70, the locking block 50 swings towards the backrest frame 30 to the first position. The locking block 50 is above the topmost locking groove 31, pulling the backrest frame 30 upward by an appropriate distance, so that the locking protrusion 51 of the locking block 50 is embedded in the corresponding locking groove 31, thus completing the downward adjustment of the backrest frame 30.

[0037] The backrest frame 30 is provided with a guide groove 33 extending vertically, and the connecting seat 20 is provided with a guide rail 24 extending vertically. The guide rail 24 is slidably embedded in the guide groove 33 from back to front, so that the backrest frame 30 is slidably mounted on the connecting seat 20. The guide rail 24 is provided with a protruding rib located on the front side of the backrest frame 30. The protruding rib limits the degree of freedom of movement of the connecting seat 20 and the backrest frame 30 in the front-back direction, so that the backrest frame 30 can move vertically and vertically relative to the connecting seat 20 relatively stably.

[0038] The seat of this utility model includes the aforementioned adaptive backrest assembly. The other structures of the seat are the same as those in the prior art and will not be described in detail here.

[0039] Finally, it should be noted that the above embodiments are only optional embodiments of this utility model and should not be used to limit the scope of protection of this utility model. Any non-substantial changes and substitutions made by those skilled in the art based on this utility model shall fall within the scope of protection claimed by this utility model.

Claims

1. An adaptive backrest assembly, characterized in that, Includes backrest bracket, backrest frame, and connecting base; The connecting seat is movably mounted on the backrest bracket so that the connecting seat can move relative to the backrest bracket in the vertical direction. The backrest bracket is provided with a groove that is recessed from its front side and extends in the vertical direction. The connecting seat is provided with a stop block that extends into the groove. A spring is provided in the groove, with the upper end of the spring abutting against the stop block and the lower end abutting against the lower end face of the groove. The backrest frame is mounted on the connecting seat and configured to move relative to the connecting seat in the vertical direction. The connecting seat is provided with a locking block that can move between a first position protruding forward from the connecting seat and a second position retracting into the connecting seat. The backrest frame is provided with multiple locking slots arranged in the vertical direction. When the locking block is in the first position, it can be engaged in one of the locking slots to limit the degree of freedom of the backrest frame to move downward relative to the connecting seat. When the locking block is in the second position, it disengages from the locking slot.

2. The adaptive backrest assembly as described in claim 1, characterized in that, The connecting seat includes a front wall and two side walls extending rearward from both sides of the front wall. The two side walls are respectively placed on both sides of the backrest bracket. Each side wall is provided with two limiting grooves extending in the vertical direction. The backrest bracket is fixedly connected to a guide post that slides through the limiting groove.

3. The adaptive backrest assembly as described in claim 2, characterized in that, The guide post is detachably fixed to the side of the backrest bracket. The guide post is provided with a limiting rib that protrudes outward from its periphery and is located on the outside of the side wall of the connecting seat.

4. The adaptive backrest assembly as described in claim 1, characterized in that, The connecting seat is provided with a guide groove, which includes a first section extending vertically and a second section extending from the bottom of the first section toward the backrest frame. A guide post is provided on the locking block, and the guide post is slidably embedded in the guide groove. The guide post slides within the second section of the guide groove to move the locking block between a first position and a second position. The backrest frame is provided with a first pushing part located above multiple locking slots and a second pushing part located below multiple locking slots. A third pushing part is provided between the lowest locking slot and the second pushing part on the backrest frame. The third pushing part is used to... When the third pushing part slides downward to contact the locking block, it pushes the locking block from the first position to the second position, so that the guide post slides to the position where the first and second sections of the guide groove meet. The second pushing part is used to push the locking block upward when the backrest frame slides upward to contact the locking block. The first pushing part is used to push the locking block downward when the backrest frame slides downward to contact the locking block. An elastic element is provided between the connecting seat and the locking block. The elastic element is used to apply elastic stress to the locking block so that the locking block always maintains the tendency to move towards the first position.

5. The adaptive backrest assembly as described in claim 4, characterized in that, A lock box is detachably fixed on the connecting seat above the stop block. The lock box has a mounting groove with an opening facing the backrest frame. A guide groove is provided on each side of the mounting groove. The lock block is embedded in the mounting groove. The two ends of the guide post protrude from the two sides of the lock block and are embedded in the two guide grooves respectively. The elastic element is a spring, and the two ends of the spring abut against the bottom wall of the mounting groove and the lock block respectively.

6. The adaptive backrest assembly as described in claim 5, characterized in that, A sliding groove is provided on each side of the mounting groove. The sliding groove is located below the guide groove and extends in the vertical direction. A sliding post is provided on the locking block. The two ends of the sliding post protrude from the two sides of the locking block and pass through the two sliding grooves. The sliding post is configured to slide along the extension direction of the sliding groove and rotate within the sliding groove.

7. The adaptive backrest assembly as described in claim 4, characterized in that, The locking block is provided with a locking protrusion that matches the shape of the locking groove; the locking groove includes a stop wall and an inclined guide wall. The inclined guide wall gradually slopes away from the connecting seat from bottom to top, and the stop wall extends from the top of the inclined guide wall towards the connecting seat. The stop wall is parallel to the front-back direction or gradually slopes downward from front to back. When the locking protrusion is placed in the locking groove, the stop wall abuts against the locking protrusion to limit the degree of freedom of the stop wall to move downward relative to the locking protrusion. The inclined guide wall is used to push the locking protrusion toward the connecting seat when the backrest frame moves upward relative to the locking block so that the locking block disengages from the locking groove.

8. The adaptive backrest assembly as described in claim 7, characterized in that, The backrest frame is provided with vertically extending clearance grooves for accommodating the lock block. The first push part is located at the top of the clearance groove, the bottom of the clearance groove forms the second push part, and the third push part is a push slope located in the clearance groove. The push slope gradually slopes from top to bottom towards the connecting seat.

9. The adaptive backrest assembly as described in claim 1, characterized in that, The backrest frame is provided with vertically extending guide grooves, and the connecting seat is provided with vertically extending guide rails, which are slidably embedded in the guide grooves.

10. A seat, characterized in that, Includes the adaptive backrest assembly as described in any one of claims 1-9.

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